That’s roughly $30 for each drawing. Sounds okay to me, but you can always find it cheaper in a place like Florida, particularly near Orlando, that’s heavy on under-employed artists and related craftspersons.
My question would be: are these hand-drawn, are they simple cartoon sketches, photoshopped semi-comps, or are they highly customized pre-vis, using shots of the actual sets and locations and products, keyed to specific camera directions, lines of script, illustrating specific camera moves, with the scenes framed and composed using specific lens widths and etc.? Done in Sketch-up, Poser, or one of the custom, purpose-designed storyboarding software programs? Is it accurate enough that a director could use it for a blueprint to place his dolly track and light grids? Then $33 sounds cheap indeed. For stick figures with little detail in a generic background… maybe not so much…
$33 per shot could be a little over, or way under, depending on what level of completeness and accuracy you are getting per frame. In any case, artists have expenses and add-on costs they need to build into their rates, so I don’t think it is ever going to be as cheap as you “think” it should. The issue should be how much use you’re getting out of each frame drawn or rendered. Will they save you money by accurately showing and predicting all the angles and setups? Will they save the client money by showing exactly what they will be paying for, helping them avoid costly re-dos later?
But “cheap” is relative; if it lands you a million-dollar account, it’s probably DIRT cheap, right?